CHBC · California Historical Building Code
Occupancy classification & change
The CHBC defines how qualified historical buildings are classified and how their occupancies may be continued or changed under tailored, preservation‑focused safety rules.
Last reviewed: July 6, 2026
Overview
This area of the California Historical Building Code (CHBC) covers how qualified historical buildings and properties are classified by use and how existing or new uses may be continued or changed. The CHBC requires that a qualified historical building be classified prior to permit issuance and describes the purpose and scope for occupancy determinations in § 8‑301.1 and § 8‑301.2 . It also directs users to Chapter 8‑3 (Use and Occupancy) for the specific rules that apply to historical properties .
Why this matters: the CHBC balances preservation and life‑safety by allowing continued historic uses and permitting changes of occupancy without automatically forcing full new‑construction compliance, provided the building meets the CHBC requirements for the new use (see § 8‑302.1 and § 8‑302.2) . Chapter 8‑3 includes practical limits and adaptations (for example occupancy separations, maximum floor area and height exceptions) so owners and design professionals can plan alterations that protect historic fabric while addressing safety and code obligations (see § 8‑302.3–§ 8‑302.5) . The CHBC also points back to general application rules and change‑of‑occupancy guidance elsewhere in the code (see § 8‑102.1.3) .
In this section
Code references
Grounded in the retrieved California Historical Building Code — click a citation to read the verbatim passage:
CHBC § 8-3 High relevance — show source text
TREATMENT. An act of work to carry out preservation, restoration, stabilization, rehabilitation or reconstruction.
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SECTION 8-301 — PURPOSE AND SCOPE
8-301.1 Purpose. The purpose of the CHBC is to provide regulations for the determination of occupancy classifications and conditions of use for qualified historical buildings or properties.
8-301.2 Scope. Every qualified historical building or property for which a permit or approval has been requested shall be classified prior to permit issuance according to its use or the character of its occupancy in accordance with the regular code and applicable provisions of this chapter.
SECTION 8-302 — GENERAL
8-302.1 Existing use. The use or character of occupancy of a qualified historical building or property, or portion thereof, shall be permitted to continue in use regardless of any period of time in which it may have remained unoccupied or in other uses, provided such building or property otherwise conforms to all applicable requirements of the CHBC.
8-302.2 Change in occupancy. The use or character of the occupancy of a qualified historical building or property may be changed from or returned to its historical use or character, provided the qualified historical building or property conforms to the requirements applicable to the new use or character of occupancy as set forth in the CHBC. Such change in occupancy shall not mandate conformance with new construction requirements as set forth in regular code.
8-302.3 Occupancy separations. Required occupancy separations of more than one hour may be reduced to one-hour fire-resistive construction with all openings protected by not less than three-fourths-hour fire-resistive assemblies of the self-closing or automatic-closing type when the building is provided with an automatic sprinkler system throughout the entire building in accordance with Section 8-410.2. Doors equipped with automatic-closing devices shall be of a type which will function upon activation of a device which responds to products of combustion other than heat.
Required occupancy separations of one hour may be omitted when the building is provided with an automatic sprinkler system throughout.
8-302.4 Maximum floor area. Regardless of the use or character of occupancy, the area of a one-story qualified historical building or property may have, but shall not exceed, a floor area of 15,000 square feet (1393.5 m [2] ) unless such an increase is otherwise permitted in regular code. Multistory qualified historical buildings (including basements and cellars) shall be in accordance with regular code requirements.
Exception: Historical buildings may be unlimited in floor area without fire-resistive area separation walls:
- When provided with an automatic sprinkler, or
- Residential occupancies of two stories or less when provided with a complete fire alarm and annunciation system and where the exiting system conforms to regular code.
8-302.5 Maximum height. The maximum height and number of stories of a qualified historical building or property shall not be limited because of construction type, provided such height or number of stories does not exceed that of its historical design.
CHBC § 8-3 High relevance — show source text
This shall include historical buildings or properties on, or determined eligible for, national, state or local historical registers or inventories, such as the National Register of Historic Places, California Register of Historical Resources, State Historical Landmarks, State Points of Historical Interest, and city or county registers, inventories or surveys of historical or architecturally significant sites, places or landmarks.
RECONSTRUCTION. The act or process of depicting, by means of new construction, the form, features and detailing of a nonsurviving site, landscape, building, property or object for the purpose of replicating its appearance at a specific period of time.
REGULAR CODE. The adopted regulations that govern the design and construction or alteration of nonhistorical buildings and properties within the jurisdiction of the enforcing agency.
REHABILITATION. The act or process of making possible a compatible use for qualified historical building or property through repair, alterations and additions while preserving those portions or features which convey its qualified historical, cultural or architectural values.
RELOCATION. The act or process of moving any qualified historical building or property or a portion of a qualified historical building or property to a new site, or a different location on the same site.
REPAIR. Renewal, reconstruction or renovation of any portion of an existing property, site or building for the purpose of its continued use.
RESTORATION. The act or process of accurately depicting the form, features and character of a qualified building or property as it appeared at a particular period of time by the means of the removal of features from other periods in its history and reconstruction of missing features from the restoration period. The limited and sensitive upgrading of mechanical, electrical and plumbing systems and other code-required work to make properties functional is appropriate within a restoration project.
STRUCTURE. That which is built or constructed, an edifice or a building of any kind, or any piece of work artificially built up or composed of parts joined together in some definite manner.
TREATMENT. An act of work to carry out preservation, restoration, stabilization, rehabilitation or reconstruction.
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SECTION 8-301 — PURPOSE AND SCOPE
8-301.1 Purpose. The purpose of the CHBC is to provide regulations for the determination of occupancy classifications and conditions of use for qualified historical buildings or properties.
8-301.2 Scope. Every qualified historical building or property for which a permit or approval has been requested shall be classified prior to permit issuance according to its use or the character of its occupancy in accordance with the regular code and applicable provisions of this chapter.
SECTION 8-302 — GENERAL
8-302.1 Existing use. The use or character of occupancy of a qualified historical building or property, or portion thereof, shall be permitted to continue in use regardless of any period of time in which it may have remained unoccupied or in other uses, provided such building or property otherwise conforms to all applicable requirements of the CHBC.
8-302.2 Change in occupancy. The use or character of the occupancy of a qualified historical building or property may be changed from or returned to its historical use or character, provided the qualified historical building or property conforms to the requirements applicable to the new use or character of occupancy as set forth in the CHBC. Such change in occupancy shall not mandate conformance with new construction requirements as set forth in regular code.
CHBC § 506.1 High relevance — show source text
SECTION 506—CHANGE OF OCCUPANCY
506.1 Compliance. A change of occupancy shall not be made in any building unless that building is made to comply with the requirements of the California Building Code for the use or occupancy. Changes of occupancy in a building or portion thereof shall be such that the existing building is not less complying with the provisions of this code than the existing building or structure was prior to the change. Subject to the approval of the code official, changes of occupancy shall be permitted without complying with all of the requirements of this code for the new occupancy, provided that the new occupancy is less hazardous, based on life and fire risk, than the existing occupancy.
Exception: The building need not be made to comply with Chapter 16 of the California Building Code unless required by Section 506.5.
506.1.1 Change in the character of use. A change of occupancy with no change of occupancy classification shall not be made to any structure that will subject the structure to any special provisions of the applicable California Codes, without approval of the code official. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
506.1.2 Change in function. [OSHPD 1R, 2, 4 and 5] A change in function shall require compliance with all the functional require- ments for new construction in the California Building Code, including requirements in Sections 1224, 1225, 1226, 1227 and 1228.
Exception [OSHPD 1R] : Hospital buildings removed from acute care service adapted for re-use as skilled nursing facilities, acute psychiatric hospitals or out-patient services of a hospital may be permitted to meet the minimum room clearances, areas and dimensions of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506.2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506.3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
506.4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
[BS] 506.5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
CHBC § 1007.1 High relevance — show source text
3 Exception 3|X|||||||||||||||||||||||| |1007||||†|†|||||||||||||||||||| |1007.1|||X|||||||||||||||||||||| |1009.2 – 1009.4||||†|†|||||||||||||||||||| |1011.2.1|||X|||||||||||||||||||||| |1011.2.2|||X|||||||||||||||||||||| |1011.4||||†|†|||||||||||||||||||| |1011.5.1|||X|||||||||||||||||||||| |1011.5.1 Exception 8||||†|†|||||||||||||||||||| |Table 1011.5|||X|||||||||||||||||||||| |1011.5.2|||X|||||||||||||||||||||| |1011.5.2 Exception 2||||†|†|||||||||||||||||||| |1011.5.4|||X|||||||||||||||||||||| |1011.5.5|||X|||||||||||||||||||||| |1011.6.1 Exception 1||||†|†|||||||||||||||||||| |1011.7.1 Exception||||†|†|||||||||||||||||||| |1011.8.2|||X||||||||||||||||||||||
The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
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User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
CHBC § 1001.2.1 High relevance — show source text
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.
SECTION 1005—MEANS OF EGRESS
1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1006—STRUCTURAL
[BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.
Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads.
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[BS] 1006.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 and 1609 of the California Building Code for the new risk category.
CHBC § 1011.6.2 High relevance — show source text
1011.6.2 Height and area for change to an equal or lesser-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category as shown in Table 1011.6, the height and area of the existing buildingshall be deemed acceptable.
1011.6.3 Fire barriers. Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.6, fire barriers in separated mixed use buildings shall comply with the fire-resistance requirements of the California Building Code .
Exception: Where the fire barriers are required to have a 1-hour fire-resistance rating, existing wood lath and plaster in good condition or existing [1] / 2 -inch-thick (12.7 mm) gypsum wallboard shall be permitted.
1011.7 Exterior wall fire-resistance ratings. Hazard categories in regard to fire-resistance ratings of exterior walls shall be in accordance with Table 1011.7.
TABLE 1011.7—EXPOSURE OF EXTERIOR WALLS HAZARD CATEGORIES Col2 RELATIVE HAZARD OCCUPANCY CLASSIFICATION 1 (Highest Hazard) H 2 F-1; M; S-1 3 A; B; E; I; R 4 (Lowest Hazard) F-2; S-2; U 2025 CALIFORNIA EXISTING BUILDING CODE 10-7
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1011.7.1 Exterior wall rating for change of occupancy classification to a higher-hazard category. Where a change of occupancy classification is made to a higher hazard category as shown in Table 1011.7, exterior walls shall have fire-resistance, exterior opening areas and opening protectives as required by the California Building Code .
Exception: A 2-hour fire-resistance rating shall be allowed where the building does not exceed three stories in height and is classified as one of the following groups: A-2 and A-3 with an occupant load of less than 300, B, F, M or S.
1011.7.2 Exterior wall rating for change of occupancy classification to an equal or lesser-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category as shown in Table 1011.7, existing exterior walls, including openings, shall be accepted.
1011.7.3 Opening protectives. Openings in exterior walls shall be protected as required by the California Building Code . Where openings in the exterior walls are required to be protected because of their distance from the lot line, the sum of the area of such openings shall not exceed 50 percent of the total area of the wall in each story.
Exceptions:
Where the California Building Code permits openings in excess of 50 percent.
Protected openings shall not be required in buildings of Group R occupancy that do not exceed three stories in height and that are located not less than 3 feet (914 mm) from the lot line.
Exterior opening protectives are not required where an automatic sprinkler system has been installed throughout.
Exterior opening protectives are not required where the change of occupancy group is to an equal or lower hazard classification in accordance with Table 1011.7.
CHBC § 1001.1 High relevance — show source text
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User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
CHBC § 8-101.1 High relevance — show source text
8-101.1 Title. These regulations shall be known as the California Historical Building Code and will be referred to herein as “the CHBC.”
8-101.2 Purpose. The purpose of the CHBC is to provide regulations for the preservation, restoration, rehabilitation, relocation or reconstruction of buildings or properties designated as qualified historical buildings or properties (as defined in Chapter 8-2). The CHBC is intended to provide solutions for the preservation of qualified historical buildings or properties, to promote sustainability, to provide access for persons with disabilities, to provide a cost-effective approach to preservation, and to provide for the reasonable safety of the occupants or users. The CHBC requires enforcing agencies to accept solutions that are reasonably equivalent to the regular code (as defined in Chapter 8-2) when dealing with qualified historical buildings or properties.
8-101.3 Intent. The intent of the CHBC is to facilitate the preservation and continuing use of qualified historical buildings or properties while providing reasonable safety for the building occupants and access for persons with disabilities.
SECTION 8-102 — APPLICATION
8-102.1 Application. The CHBC is applicable to all issues regarding code compliance for qualified historical buildings or properties. The CHBC may be used in conjunction with the regular code to provide solutions to facilitate the preservation of qualified historical buildings or properties. The CHBC shall be used by any agency with jurisdiction and whenever compliance with the code is required for qualified historical buildings or properties.
- State or local enforcing agency. The state or local enforcing agency shall apply the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, reconstruction, rehabilitation, relocation or continued use of a qualified historical building or property when so elected by the private property owner.
- State agencies. All state agencies shall apply the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, rehabilitation, safety, relocation, reconstruction or continued use of qualified historical buildings or properties.
8-102.1.1 Additions, alterations and repairs. It is the intent of the CHBC to allow nonhistorical expansion or addition to a qualified historical building or property, provided nonhistorical additions shall conform to the requirements of the regular code (as defined in Chapter 8-2).
8-102.1.2 Relocation. Relocated qualified historical buildings or properties shall be sited to comply with the regular code or with the solutions listed in the CHBC. Nonhistorical new construction related to relocation shall comply with the regular code. Reconstruction and restoration related to relocation is permitted to comply with the provisions in the CHBC.
8-102.1.3 Change of occupancy. For change of use or occupancy, see Chapter 8-3, Use and Occupancy.
8-102.1.4 Continued use. Qualified historical buildings or properties may have their existing use or occupancy continued if such use or occupancy conformed to the code or to the standards of construction in effect at the time of construction, and such use or occupancy does not constitute a distinct hazard to life safety as defined in the CHBC.
8-102.1.5 Unsafe buildings or properties. When a qualified historical building or property is determined to be unsafe as defined in the regular code, the requirements of the CHBC are applicable to the work necessary to correct the unsafe conditions. Work to remediate the buildings or properties need only address the correction of the unsafe conditions, and it shall not be required to bring the entire qualified historical building or property into compliance with regular code.
CHBC § 1.11. High relevance — show source text
The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
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Not adopted by the State of California (May be available for adoption by local ordinance. See Section 1.1.11.) (See Section 104.11 for consideration of alternative means of compliance.)
User notes:
About this chapter: Chapter 13 allows for existing buildings to be evaluated so as to show that alterations, while not meeting new construction requirements, will improve the current existing situation. Provisions are based on a numerical scoring system involving 21 various safety parameters and the degree of code compliance for each issue.
SECTION 1301—GENERAL
1301.1 Scope. The provisions of this chapter shall apply to the alteration, addition and change of occupancy of existing structures, including historic structures, as referenced in Section 301.3.3. The provisions of this chapter are intended to maintain or increase the current degree of public safety, health and general welfare in existing buildings while permitting, alteration, addition and change of occupancy without requiring full compliance with Chapters 6 through 12, except where compliance with the prescriptive method of Chapter 5 or the work area method of other provisions of this code is specifically required in this chapter.
1301.1.1 Compliance with other methods. Alterations, additions and changes of occupancy to existing structures shall comply with the provisions of this chapter or with one of the methods provided in Section 301.3.
SECTION 1302—APPLICABILITY
1302.1 General. Existing buildings in which there is work involving additions, alterations or changes of occupancy shall be made to conform to the requirements of this chapter or the provisions of Chapters 6 through 12. The provisions of Sections 1302.1.1 through 1302.1.6 shall apply to existing occupancies that will continue to be, or are proposed to be, in Groups A, B, E, F, I-2, M, R and S. These provisions shall also apply to Group U occupancies where such occupancies are undergoing a change of occupancy or a partial change in occupancy with separations in accordance with Section 1302.1.2. These provisions shall not apply to buildings with occupancies in Group H, I-1, I-3 or I-4.
1302.1.1 Change in occupancy. Where an existing building is changed to a new occupancy classification and this section is applicable, the provisions of this section for the new occupancy shall be used to determine compliance with this code.
1302.1.2 Partial change in occupancy. Where a portion of the building is changed to a new occupancy classification and that portion is separated from the remainder of the building with fire barrier or horizontal assemblies having a fire-resistance rating as required by Table 508.4 of the International Building Code or Section R302 of the International Residential Code for the separate occupancies, or with approved compliance alternatives, the portion changed shall be made to conform to the provisions of this section. Only the portion separated shall be required to be evaluated for compliance.
CHBC § 1.10.1 High relevance — show source text
Chapter 5A Prescriptive Compliance Method.
Chapter 5A provides details for the prescriptive compliance method for alteration, addition and change of occupancy of existing build- ings and structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).
Chapter 6 Classification of Work.
Chapter 6 provides an overview of the Work Area Method and defines the different classifications of work including alterations, change of occupancy, additions and historic buildings. Detailed requirements for all of these are given in subsequent Chapters 7 through 11.
Chapter 7 Alterations—Level 1.
Chapter 7 provides the technical requirements for those existing buildings that undergo Level 1 alterations as described in Section 602, which includes replacement or covering of existing materials, elements, equipment or fixtures using new materials for the same purpose. This chapter is distinguished from Chapters 8 and 9 by only involving replacement of building components with new components with no reconfiguration of space.
Chapter 8 Alterations—Level 2.
A Level 2 alteration is an alteration involving space reconfiguration that could be up to and including 50 percent of the area of the building or addition of a new building system. Level 2 alterations also include the extension or addition of any system or equipment. The purpose of Chapter 8 is to provide detailed requirements and provisions to identify the required improvements in the existing building elements, means of egress, fire protection, structural systems, energy efficiency, and other building systems include electrical, mechanical and plumbing when a building is being altered.
Chapter 9 Alterations—Level 3.
Chapter 9 provides the technical requirements for those existing buildings that undergo Level 3 alterations. Level 3 alterations are those involving alterations that cover 50 percent of the aggregate area of the building. Under certain situations, this chapter also intends to improve the safety of certain building features beyond the work area and in other parts of the building where no alteration work might be taking place.
Chapter 10 Change of Occupancy.
The purpose of Chapter 10 is to address existing buildings that are subject to a change of occupancy. This chapter is an assembly of requirements to upgrade safety without having to comply fully as a new building. A change of occupancy classification is considered a change of occupancy, however, it will involve a higher level of regulation since the use of the building has made a more significant change.
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Chapter 11 Additions.
Chapter 11 provides the requirements for additions, which are considered new construction. The requirements focus on safely integrating the addition with the existing building. This includes issues such as limiting the overall height and area of the building where the addition is not separated by a fire wall.
Chapter 12 Historic Buildings —Reserved
Chapter 12 is not adopted by the State of California. Historic buildings and structures shall comply with Part 8, Title 24, California Code of Regulations.
Chapter 13 Performance Compliance Methods.
Chapter 13 allows for existing buildings to be evaluated to show that alterations or a change of occupancy, while not meeting new construction requirements, will provide a level of safety to demonstrate compliance. Provisions are based on a numerical scoring system involving 21 safety parameters where, when evaluated, such buildings must meet a minimum overall safety score.
CHBC § 10-5 High relevance — show source text
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1011.5 Means of egress, general. Hazard categories in regard to life safety and means of egress shall be in accordance with Table 1011.5.
TABLE 1011.5—MEANS OF EGRESS HAZARD CATEGORIES Col2 RELATIVE HAZARD OCCUPANCY CLASSIFICATIONS 1 (Highest Hazard) H (Not Allowed) 2 I-2; I-3; I-4_(Not Allowed)_ 3 A; E; M; R-1; R-2; R-4 4 B; F-1; R-3; R-4, S-1 5 (Lowest Hazard) F-2; S-2; U 1011.5.1 Means of egress for change to a higher-hazard category. Where a change of occupancy classification is made to a higher-hazard category (lower number) as shown in Table 1011.5, the means of egress shall comply with the requirements of Chapter 10 of the California Building Code .
Exceptions:
Stairways shall be enclosed in compliance with the applicable provisions of Section 903.1.
Existing stairways including handrails and guards complying with the requirements of Chapter 9 shall be permitted for continued use subject to approval of the code official.
Any stairway replacing an existing stairway within a space where the pitch or slope cannot be reduced because of existing construction shall not be required to comply with the maximum riser height and minimum tread depth requirements.
Existing corridor walls constructed on both sides of wood lath and plaster in good condition or [1] / 2 -inch-thick (12.7 mm) gypsum wallboard shall be permitted. Such walls shall either terminate at the underside of a ceiling of equivalent construction or extend to the underside of the floor or roof next above.
Existing corridor doorways, transoms and other corridor openings shall comply with the requirements in Sections 804.7.1, 804.7.2 and 804.7.3.
Existing dead-end corridors shall comply with the requirements in Section 804.8.
An operable window complying with Section 1011.5.6 shall be accepted as an emergency escape and rescue opening.
In Group R-2.1 and I-2 facilities, required guards enclosing the occupiable roof areas shall be permitted to be greater than 48 inches (1219 mm) above the surface of the occupiable roof where the occupants, because of clinical needs, require restraint or containment as part of a function of a psychiatric or cognitive treatment area.
1011.5.2 Means of egress for change of use to an equal or lower-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category (higher number) as shown in Table 1011.5, existing elements of the means of egress shall comply with the requirements of Section 905 for the new occupancy classification. Newly constructed or configured means of egress shall comply with the requirements of Chapter 10 of the California Building Code .
Exceptions:
CHBC § 1006.3 High relevance — show source text
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
Reserved.
Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
[BS] 1006.4 Access to Risk Category IV. Any structure that provides operational access to an adjacent structure assigned to Risk Category IV as the result of a change of occupancy shall itself comply with Sections 1608 and 1609 of the California Building Code and Section 304.3.1 of this code. Where operational access to Risk Category IV is less than 10 feet (3048 mm) from either an interior lot line or from another structure, access protection from potential falling debris shall be provided.
SECTION 1007—ELECTRICAL
1007.1 Special occupancies. Where the occupancy of an existing building or part of an existing building is changed to one of the following special occupancies as described in the California Electrical Code, the electrical wiring and equipment of the building or portion thereof that contains the proposed occupancy shall comply with the applicable requirements of the California Electrical Code :
Hazardous locations.
Commercial garages, repair and storage.
Aircraft hangars.
Gasoline dispensing and service stations.
Bulk storage plants.
Spray application, dipping and coating processes.
Reserved.
Places of assembly.
Theaters, audience areas of motion picture and television studios, and similar locations.
Motion picture and television studios and similar locations.
Motion picture projectors.
Agricultural buildings.
1007.2 Unsafe conditions. Where the occupancy of an existing building or part of an existing building is changed, all unsafe conditions shall be corrected without requiring that all parts of the electrical system comply with the California Electrical Code .
1007.3 Service upgrade. Where the occupancy of an existing building or part of an existing building is changed, electrical service shall be upgraded to meet the requirements of the California Electrical Code for the new occupancy.
Frequently asked questions
Can a qualified historical building change occupancy without meeting full new‑construction requirements?
Yes. The CHBC permits a change or return to a historical use provided the building conforms to the CHBC requirements for the new use; such a change "shall not mandate conformance with new construction requirements as set forth in regular code" (see § 8‑302.2) .
Will an existing historic use always be allowed to continue?
Existing historic uses may continue so long as they do not create a distinct life‑safety hazard and otherwise conform to applicable CHBC provisions; the code explicitly allows continued use regardless of periods of vacancy (see § 8‑302.1) .
Where in the CHBC do I look first for occupancy questions?
Start with Chapter 8‑3 (Use and Occupancy)—notably § 8‑301 (purpose and scope) and § 8‑302 (general occupancy provisions)—and consult the CHBC application rules in Chapter 8‑1 (for links to change‑of‑occupancy direction at § 8‑102.1.3) file.
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